A berkoen is a wooden pile that is driven into the ground along waterways, ditches, and ponds to protect the bank against erosion and collapse. Together with horizontal planks (boards) or woven panels, berkoenen form a revetment — a vertical wall that prevents the bank from crumbling away. It is one of the oldest methods of bank protection in Dutch hydraulic engineering.
Characteristics
Berkoenen have specific properties that make them suitable for use in and near water:
- Wood species — Traditionally, berkoenen are made from oak, azobe, or other tropical hardwoods. Oak berkoenen can last several decades. Nowadays, pressure-treated softwood is also used, though it has a shorter lifespan.
- Dimensions — Berkoenen are typically round or square-sawn poles with a diameter or side length of 8 to 15 centimetres and a length of 1.5 to 3 metres, depending on the water depth and bank height.
- Pointed end — The bottom of a berkoen is sharpened to a point, allowing the pile to be easily driven or vibrated into the ground.
- Spacing — Berkoenen are driven into the bank soil at regular intervals (40 to 80 centimetres centre to centre), after which horizontal planks or boards are fitted between them.
Applications
Berkoenen are deployed at various locations:
- Along ditches and canals in agricultural areas
- Around ponds and water features in gardens and parks
- Along urban canals and waterways
- In the construction of marinas and jetties
- As temporary or permanent bank protection during construction projects near water
- In the creation of nature-friendly banks combined with reed mats or coconut rolls
Revetment construction
A complete revetment using berkoenen consists of:
- Berkoenen — The vertical piles, driven into the ground
- Planks or boards — Horizontal boards fastened to the berkoenen
- Waling beams — Horizontal beams connecting the tops of the berkoenen
- Ground anchors or tie rods — Anchoring into the bank for added stability on taller revetments
Why berkoenen are still used today
Despite the availability of modern materials like steel sheet piling, vinyl, and concrete, wooden berkoenen remain popular for smaller-scale applications. They blend naturally into the landscape, are relatively affordable, and can be installed without heavy machinery in many situations. In nature conservation areas, timber revetments are often preferred because they provide habitats for insects and small animals.
Related terms
- Revetment
- Sheet piling
- Bank protection
- Cofferdam
- Hydraulic engineering
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